a) Field of the Invention
The present invention relates to an automatic speed servo-control apparatus for an electrically powered walking-running exercise machine, like those known in the trade as "thread mill".
b) Brief Description of the Prior Art
As it is known any user of a conventional walking-running exercise machine must follow special procedures established by the machine's manufacturer in order to utilize this appliance with minimum risks of injuries. Mainly, these injuries may occur when the user falls while stepping in or out of the moving belt of the walking-running exercise machine.
To prevent such injuries, some walking-running exercise machines are provided with emergency cords installed on consoles in front of the machines. Nevertheless, the possibility of fall increases when the user pulls this emergency cord, because the cord produces a sudden stop instead of smooth deceleration.
Most of the conventional walking-running exercise machines are using rotary potentiometers installed on the consoles in front of the machines for varying the speed of their moving belts. This speed is adjusted as a function of the voltage generated from the rotary potentiometer and applied to the DC drive (Direct Current Drive) inputs of the walking-running exercise machine.